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linux/arch/x86/boot/bioscall.S
Peter Zijlstra 7c6dd961d0 x86/boot: Avoid using Intel mnemonics in AT&T syntax asm
With 'GNU assembler (GNU Binutils for Debian) 2.39.90.20221231' the
build now reports:

  arch/x86/realmode/rm/../../boot/bioscall.S: Assembler messages:
  arch/x86/realmode/rm/../../boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/realmode/rm/../../boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

  arch/x86/boot/bioscall.S: Assembler messages:
  arch/x86/boot/bioscall.S:35: Warning: found `movsd'; assuming `movsl' was meant
  arch/x86/boot/bioscall.S:70: Warning: found `movsd'; assuming `movsl' was meant

Which is due to:

  PR gas/29525

  Note that with the dropped CMPSD and MOVSD Intel Syntax string insn
  templates taking operands, mixed IsString/non-IsString template groups
  (with memory operands) cannot occur anymore. With that
  maybe_adjust_templates() becomes unnecessary (and is hence being
  removed).

More details: https://sourceware.org/bugzilla/show_bug.cgi?id=29525

Borislav Petkov further explains:

  " the particular problem here is is that the 'd' suffix is
    "conflicting" in the sense that you can have SSE mnemonics like movsD %xmm...
    and the same thing also for string ops (which is the case here) so apparently
    the agreement in binutils land is to use the always accepted suffixes 'l' or 'q'
    and phase out 'd' slowly... "

Fixes: 7a734e7dd9 ("x86, setup: "glove box" BIOS calls -- infrastructure")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/Y71I3Ex2pvIxMpsP@hirez.programming.kicks-ass.net
2023-01-10 13:03:23 +01:00

80 lines
1.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-or-later */
/* -----------------------------------------------------------------------
*
* Copyright 2009-2014 Intel Corporation; author H. Peter Anvin
*
* ----------------------------------------------------------------------- */
/*
* "Glove box" for BIOS calls. Avoids the constant problems with BIOSes
* touching registers they shouldn't be.
*/
.code16
.section ".inittext","ax"
.globl intcall
.type intcall, @function
intcall:
/* Self-modify the INT instruction. Ugly, but works. */
cmpb %al, 3f
je 1f
movb %al, 3f
jmp 1f /* Synchronize pipeline */
1:
/* Save state */
pushfl
pushw %fs
pushw %gs
pushal
/* Copy input state to stack frame */
subw $44, %sp
movw %dx, %si
movw %sp, %di
movw $11, %cx
rep; movsl
/* Pop full state from the stack */
popal
popw %gs
popw %fs
popw %es
popw %ds
popfl
/* Actual INT */
.byte 0xcd /* INT opcode */
3: .byte 0
/* Push full state to the stack */
pushfl
pushw %ds
pushw %es
pushw %fs
pushw %gs
pushal
/* Re-establish C environment invariants */
cld
movzwl %sp, %esp
movw %cs, %ax
movw %ax, %ds
movw %ax, %es
/* Copy output state from stack frame */
movw 68(%esp), %di /* Original %cx == 3rd argument */
andw %di, %di
jz 4f
movw %sp, %si
movw $11, %cx
rep; movsl
4: addw $44, %sp
/* Restore state and return */
popal
popw %gs
popw %fs
popfl
retl
.size intcall, .-intcall